Google has just begun rolling out Android 5.1 Lollipop in a number of devices, including Nexus 6 and 5, HTC One M7 GPE, and Motorola Droid Turbo, Moto G, and Moto X, and is slated to come in more devices soon.

Nexus 6 and 5 devices with build number LMY47l have received the update earlier today after a new factory image was released, apart from the previous Nexus 6 with the latest Android maintenance release with build number LMY47e.

This update comes to a fourth Nexus 6 device. Android 5.1 comes to Nexus 6 first with build number LMY22E, second with build number LMY29C, and third with build number LMY29D. It also comes second to Nexus 5, first with build number LMY29C.

Aside from bug fixes on memory leak and SIM card handling, Android 5.1 Lollipop update will feature several additions, changes and improvements for Nexus 6 and 5 devices.

On-body Detection

On-body detection prevents locking Nexus 6 and 5 when unlocking it with a pattern or PIN, unless it does set down in itself. This process works through accelerometer.

Smart Wi-Fi Connection

A smarter Wi-Fi only automatically detects strong signals and connects to it if accessible, giving easier task for users to choose which connection is irksome, and which is good

Device Protection

Device protection features will help users secure their smartphones well. With this feature, it makes difficult for someone to break into the user's smartphone. When stolen, the device will remain locked even after resetting it to factory settings, unless a registered Google password is logged in. Device protection will automatically be initiated for phones using security system like a PIN code. Aside from Nexus 6 and 5, device protection is also available on Nexus 9 devices.

HD Voice Calls

High-definition audio now supports Android 5.1 with a promising crystal-clear voice call quality on compatible Nexus devices, including T-Mobile and Verizon versions. A strong signal will also help improve transmit audio.

Quick Settings on the Lock Screen

Quick settings in Android 5.0 enables users to pick apps or services by it rolling down. In Android 5.1, quick settings can be accessed through Nexus 6 and 5's lock screen, regardless if the device is PIN-activated. This feature makes launching flashlight, Wi-Fi, Bluetooth, NFC, etc. easier. The new quick settings is also customizable by adding or removing apps and/or service icons.

New Priority Mode

Priority mode first became part of Android 5.0 to enable users what kind of notification sounds they would want to hear as per preference. This feature is best used when users sleep. In Android 5.1, priority mode will be turned off automatically when next alarm gets terminated.

Other features include the comeback of silent mode, fix for sudden app shutdowns, efficient batter and RAM management, fix for Okay Google function, changes in the Material Design's color palette, and a lot more.